In a vacuum conveyor belt for receiving, conveying and depositing planar objects, wherein the vacuum conveyor belt has a circulating drive, and a U-profile, wherein the U-profile has a conveying passage and a return passage, and a conveyor belt, wherein the U-profile on the return passage side includes a holder element. An example isolation circuit includes an isolation barrier, a burst encoder in a first circuit, and an edge pattern detector in a second circuit. In the diffusion sheet arranged as described above, light incident on the unit lens portions from a light incident side is totally reflected on the surfaces corresponding to the side segments of the approximately trapezoidal sections vertical to the long-axis direction of the unit lens portions and outgoes from the light outgoing side.